PLAU and breast carcinoma: Although we did not further address the detailed mechanism of TGF-β-mediated macrophage activation, TGF-β has been reported to induce the expression of urokinase-type plasminogen activator (uPA) in macrophages, which leads to the degradation of the basement membrane or the extracellular matrix by the local invasion or metastasis of breast cancer cells [69,70].